1. Field of the Invention
The invention relates to a circuit board using for a communication connector. More specifically, it relates to a circuit board with a circular capacitor and a via capacitor.
2. Description of the Prior Art
Generally, high frequency signals are transmitted by a connecting wire and a connector, wherein the crosstalk signal interference is reduced by making capacitors couple on the circuit board. As shown in FIG. 1A, the connector has a plug (not shown) and a jack 1. Generally speaking, the plug comprises a plurality of conducting wires, wherein the conducting wires are paralleled with each other. The jack 1 comprises a body 11 and a circuit board 12 (e.g. (printed circuit board, PCB)). Recently, making capacitors on the circuit board of the plug is to use parallel plate capacitors (U.S. Pat. No. 7,658,651), interdigital capacitors (U.S. Pat. No. 5,997,358), or via capacitors (U.S. Pat. No. 5,618,185). As shown in FIG. 1B-FIG. 1D, FIG. 1B is a schematic diagram of a known interdigital capacitor. FIG. 1C is a schematic diagram of a known parallel plate capacitor (dashed mark). FIG. 1D is a schematic diagram of a known via capacitor.
However, with the raise of the frequency, the crosstalk interference is more serious so that the much larger coupled capacitance is needed to suppress the crosstalk signal interference. Accordingly, the area of the known capacitor will increase so that the error from process will increase. Therefore, how to raise the capacitance area efficiency to reduce the cost and error is an important issue which the applicant concerns about.